I have an 86 SVO and ran into the same problem. In my case there was a reinforcing wire in the intake hose between the turbo and air meter that was missing. I found one in an old intake hose off of an 83 Turbo Coupe that was too long but worked fine after I cut it to fit. No problems since. Hopefully this is your problem also since it only took about 30 minutes to correct. Good Luck. Enjoy your SVO.